net-mgmt/netdata: Update to new release of 1.7.0

This version update includes:

• Fix of building on FreeBSD 12 included on upstream.
• netdata now monitors ZFS (on Linux and FreeBSD)!
• netdata now monitors ElasticSearch, RabbitMQ, Go applications (via expvar), ipfw (on FreeBSD 11), samba, squid logs (with web_log plugin!).
• netdata is now a (very fast) fully featured statsd server and the only one with automatic visualization.

Reviewed by: mat (mentor)
Approved by: mat (mentor)
Sponsored by: Netzkommune GmbH
Differential Revision: https://reviews.freebsd.org/D11626